A tank where your character peeps its head out of the hatch, like make Guardian from 7s.

ULTIMATE MOUNTS: Bahamut, Ultima Weapon, Perfect Alexander

Or, Brute Justice and have it be like the Cactuar thing you get from the gold saucer, where four WoL's are hanging off of it or on top depending who is ridding pillion.

CRUISE CHASER - literally already an 8 person mount in the fight for a few brief moments.